alchemical fire does not benefit puddle punch until you heavy melee

[scientific]

the 50% weapon damage buff you gain against enemies standing in alchemical fire does not apply to viscous' puddle punch until he heavy melees sometime after hero selection. quick meleeing seems to give partial benefit.

some things not covered in the attached video:

• it did not seem to matter if i melee'd or bought alchemical fire first.
• if i swapped characters from and back to viscous, i would have to melee again to get alchemical fire to work.
• i have yet to find another item besides alchemical fire that this interaction happens with.